Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (806fdcce) · Commits · e / devices / android_kernel_fairphone_FP3

Documentation/x86/protection-keys.txt

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			Memory Protection Keys for Userspace (PKU aka PKEYs) is a CPU feature
			which will be found on future Intel CPUs.

			Memory Protection Keys provides a mechanism for enforcing page-based
			protections, but without requiring modification of the page tables
			when an application changes protection domains. It works by
			dedicating 4 previously ignored bits in each page table entry to a
			"protection key", giving 16 possible keys.

			There is also a new user-accessible register (PKRU) with two separate
			bits (Access Disable and Write Disable) for each key. Being a CPU
			register, PKRU is inherently thread-local, potentially giving each
			thread a different set of protections from every other thread.

			There are two new instructions (RDPKRU/WRPKRU) for reading and writing
			to the new register. The feature is only available in 64-bit mode,
			even though there is theoretically space in the PAE PTEs. These
			permissions are enforced on data access only and have no effect on
			instruction fetches.

			=========================== Config Option ===========================

			This config option adds approximately 1.5kb of text. and 50 bytes of
			data to the executable. A workload which does large O_DIRECT reads
			of holes in XFS files was run to exercise get_user_pages_fast(). No
			performance delta was observed with the config option
			enabled or disabled.

+13 −1

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	@@ -26,7 +26,7 @@ targets := vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2 vmlinux.bin.lzma \
	vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4		vmlinux.bin.xz vmlinux.bin.lzo vmlinux.bin.lz4

	KBUILD_CFLAGS := -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2		KBUILD_CFLAGS := -m$(BITS) -D__KERNEL__ $(LINUX_INCLUDE) -O2
	KBUILD_CFLAGS += -fno-strict-aliasing -fPIC		KBUILD_CFLAGS += -fno-strict-aliasing $(call cc-option, -fPIE, -fPIC)
	KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING		KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
	cflags-$(CONFIG_X86_32) := -march=i386		cflags-$(CONFIG_X86_32) := -march=i386
	cflags-$(CONFIG_X86_64) := -mcmodel=small		cflags-$(CONFIG_X86_64) := -mcmodel=small
	@@ -40,6 +40,18 @@ GCOV_PROFILE := n
	UBSAN_SANITIZE :=n		UBSAN_SANITIZE :=n

	LDFLAGS := -m elf_$(UTS_MACHINE)		LDFLAGS := -m elf_$(UTS_MACHINE)
			ifeq ($(CONFIG_RELOCATABLE),y)
			# If kernel is relocatable, build compressed kernel as PIE.
			ifeq ($(CONFIG_X86_32),y)
			LDFLAGS += $(call ld-option, -pie) $(call ld-option, --no-dynamic-linker)
			else
			# To build 64-bit compressed kernel as PIE, we disable relocation
			# overflow check to avoid relocation overflow error with a new linker
			# command-line option, -z noreloc-overflow.
			LDFLAGS += $(shell $(LD) --help 2>&1 \| grep -q "\-z noreloc-overflow" \
			&& echo "-z noreloc-overflow -pie --no-dynamic-linker")
			endif
			endif
	LDFLAGS_vmlinux := -T		LDFLAGS_vmlinux := -T

	hostprogs-y := mkpiggy		hostprogs-y := mkpiggy

+28 −0

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	@@ -31,6 +31,34 @@
	#include <asm/asm-offsets.h>		#include <asm/asm-offsets.h>
	#include <asm/bootparam.h>		#include <asm/bootparam.h>

			/*
			* The 32-bit x86 assembler in binutils 2.26 will generate R_386_GOT32X
			* relocation to get the symbol address in PIC. When the compressed x86
			* kernel isn't built as PIC, the linker optimizes R_386_GOT32X
			* relocations to their fixed symbol addresses. However, when the
			* compressed x86 kernel is loaded at a different address, it leads
			* to the following load failure:
			*
			* Failed to allocate space for phdrs
			*
			* during the decompression stage.
			*
			* If the compressed x86 kernel is relocatable at run-time, it should be
			* compiled with -fPIE, instead of -fPIC, if possible and should be built as
			* Position Independent Executable (PIE) so that linker won't optimize
			* R_386_GOT32X relocation to its fixed symbol address. Older
			* linkers generate R_386_32 relocations against locally defined symbols,
			* _bss, _ebss, _got and _egot, in PIE. It isn't wrong, just less
			* optimal than R_386_RELATIVE. But the x86 kernel fails to properly handle
			* R_386_32 relocations when relocating the kernel. To generate
			* R_386_RELATIVE relocations, we mark _bss, _ebss, _got and _egot as
			* hidden:
			*/
			.hidden _bss
			.hidden _ebss
			.hidden _got
			.hidden _egot

	__HEAD		__HEAD
	ENTRY(startup_32)		ENTRY(startup_32)
	#ifdef CONFIG_EFI_STUB		#ifdef CONFIG_EFI_STUB

+8 −0

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	@@ -33,6 +33,14 @@
	#include <asm/asm-offsets.h>		#include <asm/asm-offsets.h>
	#include <asm/bootparam.h>		#include <asm/bootparam.h>

			/*
			* Locally defined symbols should be marked hidden:
			*/
			.hidden _bss
			.hidden _ebss
			.hidden _got
			.hidden _egot

	__HEAD		__HEAD
	.code32		.code32
	ENTRY(startup_32)		ENTRY(startup_32)

+2 −2

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	@@ -29,7 +29,7 @@ static char gen_pool_buf[MCE_POOLSZ];
	void mce_gen_pool_process(void)		void mce_gen_pool_process(void)
	{		{
	struct llist_node *head;		struct llist_node *head;
	struct mce_evt_llist *node;		struct mce_evt_llist node, tmp;
	struct mce *mce;		struct mce *mce;

	head = llist_del_all(&mce_event_llist);		head = llist_del_all(&mce_event_llist);
	@@ -37,7 +37,7 @@ void mce_gen_pool_process(void)
	return;		return;

	head = llist_reverse_order(head);		head = llist_reverse_order(head);
	llist_for_each_entry(node, head, llnode) {		llist_for_each_entry_safe(node, tmp, head, llnode) {
	mce = &node->mce;		mce = &node->mce;
	atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);		atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
	gen_pool_free(mce_evt_pool, (unsigned long)node, sizeof(*node));		gen_pool_free(mce_evt_pool, (unsigned long)node, sizeof(*node));